Existing mathematical models suggest that gene-culture coevolution favours a conformist bias in social learning, that is, a psychological mechanism to preferentially acquire the most common cultural variants. Here we show that this conclusion relies on specific assumptions that seem unrealistic, such as that all cultural variants are known to every individual. We present two models that remove these assumptions, showing that: 1) the rate of cultural evolution and the adaptive value of culture are higher in a population in which individuals pick cultural variants at random (Random strategy) rather than picking the most common one (Conform strategy); 2) in genetic evolution the Random strategy out-competes the Conform strategy, unless cultural evolution is very slow, in which case Conform and Random usually coexist; 3) the individuals’ ability to evaluate cultural variants is a more important determinant of the adaptive value of culture than frequency-based choice strategies. We also review existing empirical literature and game-theoretic arguments for conformity, finding neither strong empirical evidence nor a strong theoretical expectation for a general conformist bias. Our own vignette study of social learning shows that people may indeed use different social learning strategies depending on context.
We investigated whether a sexual preference for smoking can be related to past experiences of parental smoking during childhood, as predicted by the theory of sexual imprinting, but also by sexual conditioning theory. In a sample of over 4000 respondents to five Internet surveys on sexual preferences, we found that parental smoking correlates with increased attraction to smoking in self-reported hetero- and homosexual males. Maternal smoking was associated with an increase in attraction to smoking both in hetero- and homosexual males, while paternal smoking was associated with an increase in attraction to smoking only in males who prefer male partners. We could not explain these findings by considering other factors than parental smoking habits, such as possibly biased reporting, indicators of a sexually liberal lifestyle or phenotype matching. Our data are consistent with the hypothesis that sexual preferences are acquired early in life by exposure to stimuli provided by individuals in the child's environment, such as caregivers. The sex specificity of the parental effect is consistent with sexual imprinting theory but not with conditioning theory.